Current collectors are main components of electrochemical batteries. The current collectors are used as electron transfer channels for electrons formed in electrochemical reactions of the batteries to an external circuit to provide current. Performances of the electrochemical batteries are affected by the performances of the current collectors.
Materials of the current collectors are usually metal foils, such as copper or aluminum foils. These kinds of current collectors are easily oxidized to form passive films, or corroded with electrolytes of the electrochemical batteries to form insulating layers on the surface of the current collectors. The passive films or insulating layers may increase contact resistances between the current collectors and electrode active materials disposed thereon. Thus, capacities and efficiencies of energy transfer of the electrochemical batteries may be decreased.